The present invention relates generally to the field of welding metallic materials.
The advantages attending the use of automatic fillet and butt welding apparatus, wherein the welding tip of a welding torch is adjustably oscillatable in transverse passes across the weld axis, while being propelled axially along the weld axis, has heretofore been generally known and appreciated from U.S. Pat. No. 3,843,866. Such apparatus, however, has in the main been of quite large size and relatively expensive, and such known apparatus is indeed too bulky and expensive to justify its extensive use.
There has therefore been a growing and present need for an economical, small sized welding apparatus, particularly of the type which may be hand-operated, and which could be depended upon to produce welds comparable to those produced by the larger apparatus as known from the aforementioned patent, and which preferably would permit the use, without modifying changes, of a standard available hand-held torch, and by the use of which an essentially unskilled person could repeatedly produce superior long and continuous welds during relatively long operating periods.
Attempts to produce such a hand-operated welding apparatus have heretofore been only moderately successful. For example, it has been known generally from U.S. Pat. No. 3,201,561 to provide a hand-operated welding gun or torch which is supported upon a power propelled wheeled carriage that is guided along the weld joint. The apparatus as disclosed in this patent is designed for and limited to movement of the welding tip axially along the weld. It is therefore only possible in this case to make an axially extending bead weld of limited width. It will therefore be appreciated that the apparatus as exemplified by this patent is not adapted to move the tip in a manner to produce the desired transverse oscillations of the tip so as to produce desirable welds of increased and greater width than are possible in the bead type of weld, while propelling the apparatus along the weld joint.
Briefly, according to the present invention, the hand-held welding apparatus utilizes a standard hand-held welding gun or torch which is releasably supported in a uniquely arranged pivotally mounted cradle on the carriage structure, the torch being supported in a position such that the welding tip will occupy a proper welding position with respect to the weld joint. Power means are utilized to propel the carriage along the weld joint and to simultaneously synchronously rock the cradle in a manner to oscillate the tip of the welding torch in transverse passes of the weld joint. In a preferred embodiment, a single power source is utilized and connected, through speed changers having predetermined ratios, respectively with the driving connections for the propelling means and the cradle-rocking means, whereby the speed of oscillation of the welding tip of the torch in relation to the propelled speed of the carriage may be maintained at a predetermined ratio. Provision is also made in the driving connection for the cradle for adjusting the extent of cradle rocking, and the concomitant extent of oscillation of the welding tip of the torch between the range limits of zero and a predetermined maximum value.